Combined magnetic regulator and transformer



0a. 29, 1968 J. A. FINGERETT 3, 8

COMBINED MAGNETIC REGULATOR AND TRANSFORMER 4 Sheets-Sheet 1 Filed Feb.28, 1966 INVENTOR. 8:00 A. mvaenerr Pac Oct. 29, 1968 J. A. FINGERETT3,408,554

COMBINED MAGNETIC REGULATOR Filed Feb. 28, 1966 A ac AND TRANSFORMER 4Sheets-Sheet 2 INVENTOR, JOSEPH A .Fl/VGERET? ATTORNEY Oct. 29, 19683,408,554

COMBINED MAGNETIC REGULATOR AND TRANSFORMER J. A. FINGERETT 4Sheets-Sheet 3 Filed Feb. 28, 1966 INVENTOR JOSEPH A F/IVGfRETT wz Ms b6080 .SGQvSu wbkviwwbw wweio m ATTORNEY Oct. 29, 1968 J A, HNGERETT3,408,554

COMBINED MAGNETIC REGULATOR AND TRANSFORMER Filed Feb. 28, 1966 4Sheets-Sheet 4 OUTPUT INVENTOR. JOSEPH A. FINGERETT ATTORNEY 3,408,554COMBINED MAGNETIC REGULATOR AND TRANSFORMER Joseph A. Fingerett, VanNuys, Calif., assignor t International Telephone and TelegraphCorporation, Nutley,

.J., a corporation of Maryland Filed Feb. 28, 1966, Ser. No. 530,309 11Claims. (Cl. 321---18) ABSTRACT OF THE DISCLOSURE A magnetic regulatorcompactly combined with a transformer by winding primary and secondarytransformer and maintain the voltage across said load substantiallyconstant regardless of variations in the AC. input voltage or loadimpedance.

This invention relates to magnetic regulators and more particularly to acombined magnetic regulator and transformer.

A feature of this invention is that by winding a common transformer andmagnetic regulator.

The above-mentioned and other objects and features of this inventionwill become apparent by reference to the following description taken inconjunction with the acaccompanying drawings in which:

FIGURE 1 is a schematic illustration of a magnetic regulator andtransformer according to this invention;

FIGURE 2 is a schematic illustration of the waveforms generated atvarious points in the circuit of FIGURE 1;

FIGURE 3 is a schematic illustration of a feedback-type regulatedvoltage supply according to this invention;

FIGURE 4 is a representation of the physical structure of thetransformer and magnetic regulator according to this invention;

FIGURE 5 is a schematic diagram of a 3-phase circuit according to theprinciples of this invention, and

FIGURE 6 is an illustration of the Waveforms generated at various pointsin the circuit of FIGURE 5.

i United States Patent 0 is the same as the alternating current supplymultipliet by either the step-up or step-down ratio between winding:Essentially, the coaction of windings W1 anc of winding W2 is coupled tothe load R via diode CR2 and a full Wave rectifier comprising diodes CR3and CR4. Connected between the full wave rectifier and the load is tothe output signal produced across winding W2.

Windings W4A and W4B coupled with the Windings on the primary side ofsaid transformers (windings W1, W3A and W3B) operate as a standardmagnetic controller, the operation of which is widely known in the artand is described in numerous textbooks and articles (see for example,Magnetic-Amplifier Circuits by Geyger, second edition, pages 264-268).Therefore, a description thereof will not be undertaken here. FIGURES 2Athrough 2H illustrate the waveforms appearing at various points in themagnetic regulator section of the circuit of FIGURE 1 which compriseswindings W1, W3A, W3B, W4A and W4B. The output of the alternatingcurrent e is shown in FIGURE 2A as a square wave in order to simplify ananalysis of the circuit. It is apparent that many other alternatingcurrent signals may be utilized instead of a square W4B, respectively.

The output of winding W2 diodes CR3 and CR4 and is coupled to the load Rvia a diode CR2. The output voltage supplied to the load R when E =0 ismerely a full wave rectified version of the alternating input signal.This output is illustrated in FIG- generate the signal shown in FIGURE2K. When E is again zero, the output to load R is merely the full waverectified alternating signal (see magnitude of DC. control signal E Asshown in FIG- URE 2 when the control signal E is decreased (see signal23, FIGURE 2B) pulses of shorter duration is full wave rectified byFIGURE 3 illustrates the basic circuit of FIGURE 1 ut further includingmeans for developing an error voltge E proportional to the deviation ofthe output voltage rom a desired value. The error voltage E is obtainedby means of the differential coupling of R1, R2, R3 and refernce diodeCR7. The junction between resistor R3 and refrence diode CR7 is positivewith respect to the junction )etween resistors R1 and R2. The D.C.voltage E obtained rom this differential connection is applied towindings WSA and W3B in the same manner as was the control signal E inFIGURE 1. The operation of this circuit is identical to the operation ofthe circuit of FIGURE 1. If the voltage across resistor R increases, theerror voltage E will decrease, thereby causing the duration of thepulses added to the output of the full wave rectifier to decrease. Thisdecreases the average voltage supplied to the load. Conversely, when thevoltage across R decreases, E will increase, thereby increasing theduration of the pulses added to the output of said full wave rectifier.In this manner it is seen that the circuit of FIGURE 3 operates as avoltage regulated supply. The circuit of FIGURE 3 utilizes a bridge-typefull wave rectifier comprising diodes CR3- CR6 instead of the twodiode-type full wave rectifier shown in FIGURE 1. This substitution hasno effect on the operation of the circuit and is merely shown by way ofexample.

FIGURE 4 illustrates a physical embodiment of the transformer andregulator according to this invention. It is seen that windings W1 andW2 are wound in common on cores 2 and 3 to provide the aforementionedadvantages. As was previously mentioned, the novel part of thisinvention lies in the addition of winding W2 to the previously knownmagnetic regulators and in the manner of placing windings W1 and W2 incommon onto two transformer cores. In this manner the amount of ironcore required for a given power output is substantially reduced over theprior art circuits which utilize separate regulators and transformers.

In FIGURE there is shown a schematic diagram of a 3-phase circuitaccording to this invention. Applied to the primary windings P through Pis a 3-phase alternating current source. Also wound on the cores areprimary control windings C through C to which is applied control voltageE The secondary windings S through S are coupled to load R via diodes Dthrough D Secondary windings S through S are also coupled to load R viadiodes D5 through D such that the output from windings 8 -8 and from S Sare additive at load R10. Note that the windings having the samesubscripts are wound on the same cores. This circuit operatesessentially in the same manner as three single phase structures (asshown in FIGURE 1 for example) coupled together and operating into acommon load. In FIGURE 5 secondary windings S '-S supply a signalproportional to the alternating input signal to the load-Therefore, theoutput to the common load R comprises the voltage pulses developed bythe regulator portion of the circuit (windings 8 -8 superimposed on thefull wave rectified version of the input signal which is supplied bywindings S -S Looking at one phase of the circuit of FIGURE 5, it isseen that windings P and P S and S S and S and C and C are analogous tothe windings W1, W4A and W4B, W2 and W3A and W3B, respectively, as shownin the circuit of FIGURE 1. Note that in the discussion of the 3-phasesystem below the alternating current source is a three phase sinusoidalwaveform as shown in FIG- URE 6A instead of the square wave input shownin FIG- URE 2A. It is apparent that any three phase alternating currentinput signal may be used and that the sinusoidal waveform is shownmerely by way of example. A brief description of the circuit shown inFIGURE 5 taken in conjunction with the waveforms shown in FIGURE 6appears below.

For the purposes of the following discussion it is assumed that windingsS -S are not connected in the cirthe fact that P and P 4 cuit and theonly output signal to the load R is supplied by windings S -S via diodesDl-D4. The relationships:

(1) E -4.44 fN I (II19.X)

and:

(7) E =KN in) (P dt Pe 6(t) (P will yield a Et=0 1 since EAB+EBC+ECA:0

This merely states that the sum of the fluxes must be zero. This isevident since Note that Equations 14, 15, and 16 are imposed by are inseries across E etc. During the portion of each cycle that both coresegments are unsaturated, a second condition can be imposed (see FIGURE5).

The time that Equation 17 is effective is from the zero crossing of theappropriate phase of the supply voltage, until saturation of one fluxpath of the pair. During this time, the control windings present arelatively high input impedance, and the current flow is related to thedifferential impedance of two unsaturated cores operating at differentvoltage levels.

In FIGURE 6, the three phase alternating current supply potential isshown, with typical waveforms for E and E E and E E and E will bepairwise identical, except for the relative phase displacement of thecorresponding primary sources. The output resulting from the system isshown, for saturation of the first core in each pair at It is possibleto provide for saturation at any phase angle between 90 and thecorresponding output level going from maximum to minimum. The minimumoutput obtainable from this circuit is zero.

FIGURE 5 will now be discussed assuming that secondary windings S '-Sare connected in the circuit as shown. These secondaries are seriesconnected as are the primaries, so that a conventional three phaserectified output is obtained therefrom b means of diodes DS-D10. Sincewindings S and S are coupled together in the same relationship as arewindings P and P the voltage across this series pair is related to theprimary voltage through the turns ratio used. The differential voltagewill not appear across the series pair.

The output obtained from windings 8 -3 (see FIG- URES 5 and 6) issuperimposed onto the output obtained from the full wave rectifiedoutput of windings Sf-S This represents the three phase equivalent ofthe single phase circuit previously described with reference to FIG-URES l and 3.

It should be noted that the output ripple frequency from the three phasecontroller is at six times the supply frequency, even though only threerectifiers are used. As

was previously seen, in the single phase unit the ripple frequency wastwice the supply frequency.

It is pointed out that a sensing circuit coupled from the load R tocontrol voltage E may be added to this circuit in the same manner as inlated 3-phase voltage supply. It is not shown in the drawings inconjunction with the 3-phase circuit for the sake of clarity.

While I have described above the principles of my invention inconnection with specific apparatus, it is to be invention, as setforthin the accompanying claims.

I claim:

1. A combined magnetic regulator and transformer comprising:

a first transformer core having first and second primary windings andfirst and second secondary windings;

core having third and fourth primary windings and third and fourthsecondary windings;

said first and third primary windings being coupled in series aiding,said first and third secondary windings being coupled in series aiding,said second and fourth primary windings being coupled in seriesopposing, and said second and fourth secondary windings being coupled inseries opposing;

means for applying an alternating current (source) to said first andthird primary windings;

output means coupled to said first and third secondary windings;

means for applying a control signal to said second and fourth primarywindings; and

means coupling said second and fourth secondary windings to said outputmeans to maintain an output voltage proportional to said alternatingcurrent and said control signal.

2. A combined magnetic regulator and transformer according to claim 1wherein said means for applying a control signal comprises:

means coupled to said output means for developing an error voltageproportional to the deviation of the output signal across said outputmeans from a desired value; and

means coupling said error voltage to said second and fourth primarywindings to maintain said output signal substantially constant.

3. The device of claim 2 wherein said means for developing an errorvoltage comprises a differential voltage detector coupled across saidoutput means.

4. The device of claim 3 wherein said differential detector comprises:

first and second resistors coupled in series and across said outputmeans;

a third resistor;

a voltage reference diode;

means coupling said third resistor and said reference diode in referencediode.

5. A combined magnetic regulator and transformer comprising:

a first transformer core having first primary windings and firstsecondary windings thereon;

a second transformer core having second primary windings and secondsecondary windings thereon;

third primary and third secondary windings wound in common on both ofsaid cores;

means for applying an alternating current signal to said third primarywindings;

output means coupled to said third secondary windings;

means for applying a control signal to said first and second primarywindings; and

means coupling said first and second secondary wind ings to said outputmeans to maintain an output volt age proportional to said alternatingcurrent signa and said control signal.

6. A combined magnetic regulator and transformer comprising:

a first transformer core having first and second primary windings andfirst and second secondary windings thereon;

a second transformer core having third and fourth pri mary windings andthird and fourth secondary windings thereon;

means for applying an alternating current signal to said first and thirdprimary windings;

a full wave rectifier coupled to said first and third secondarywindings;

a first diode coupled to the output of said full wave rectifier;

a low pass filter coupled to said diode;

an output utilization means;

means for applying a control signal to said second and fourth primarywindings; and

means coupling said second and fourth secondary windings to said lowpass filter to maintain an output voltage proportional to saidalternating current signal and said control signal.

7. The device of claim 6 wherein said means coupling said second andfourth secondary windings to said low pass 8. A combined 3-phasemagnetic reguilator and transformer comprising:

a first transformer core having first and second primary windings andfirst and second secondary windings;

a second transformer core having third and fourth primary windings andthird and fourth secondary windings;

means for applying one phase of a 3-phase alternating current signal tosaid first and third primary windings;

a third transformer core having fifth and sixth primary windings andfifth and sixth secondary windings;

a fourth transformer core having seventh and eighth primary windings andseventh and eighth secondary windings;

means for applying a second phase of a 3-phase alternating currentsignal to said fifth and seventh primary windings;

a fifth transformer core windings and ninth primary windings andeleventh and twelfth secondary windings;

means for applying the third phase of a 3-phase alternating currentsignal to said ninth and eleventh primary windings;

means for applying a control signal to said second, fourth, sixth,eighth, tenth and twelfth primary windings; and

9. The device of claim 8 wherein said first and third in series aiding,said fifth are coupled in series aiding, said ninth and eleventh primarywindings are coupled in series aiding, said second and fourth primarywindings are coupled in series opposing, said sixth and eighth primarywindings are coupled in series opposing, said tenth and twelfth primarywindings are coupled in series opposing, said first and third secondarywindings are coupled in series aiding, said fifth and seventh secondaryvindings are coupled in series aiding, said ninth and :leventh secondarywindings are coupled in series aiding, ;aid second and fourth secondarywindings are coupled in series opposing, said sixth and eighth secondarywindings are coupled in series opposing and said tenth and twelfthsecondary windings are coupled in series opposing.

10. The device of claim 9 wherein said first, third, fifth, seventh,ninth, and eleventh primary windings are coupled in a 3-phase deltaconfiguration, said second, fourth, sixth, eighth, tenth, and twelfthprimary windings are coupled in series and to a DC. control signal, saidfirst, third, fifth, seventh, ninth and eleventh secondary windings arecoupled together in a 3-phase Y configuration and said second, fourth,sixth, eighth, tenth and twelfth secondary windings are coupled togetherin a 3-phase Y configuration.

11. The device of claim 10 further comprising a plurality of diodes,

each endpoint of the legs of said Y configurations and each neutralpoint of said Y configurations being coupled to said output means ralityof diodes.

via oneof said plu- 5 References Cited UNITED STATES PATENTS 1,997,6574/1935 Schmutz 321-24 XR 2,777,073 1/1957 Fingerett et a1. 323-56 XR2,777,986 1/1957 Bennett 323-56 10 2,885,627 5/1959 Holt 323-563,112,440 11/1963 Moyer 323-56 3,315,151 4/1967 Wentworth 323-56 5 LEET. HIX, Primary Examiner.

W. M. SHOOP, JR., Assistant Examiner.

